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Alan64

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Everything posted by Alan64

  1. ...at last, and the first in over a fortnight. Looking eastward... Two afocal views of the Andromeda galaxy via the 150mm f/5 Newtonian and the 40mm Plossl... ...alas, only the core. Would that my 200mm f/5 was completed; although I do have my doubts as to it being that much more of an improvement over the 150mm.
  2. It might very well be less expensive to order a kit from outside of India, and not necessarily an Orion-branded. I realise that there may be duties to pay, but still. Also, in getting a kit with electronics and motors, will there be a repair facility there in India in the event of failure? The telescopes are manufactured just to the north in China. Have you checked to see if any vendors there carry a similar kit?
  3. Saswata, In my experience, I've come to find that the 6" f/5 Newtonian is a GREAT all-around telescope; well-balanced between observing within the solar system(the Moon and planets), and also beyond into deep space(galaxies, nebulae, star clusters). Its only drawback is that it's not suitable for daytime use, except for solar-observing. Personally, I do not consider that a drawback given its many advantages. Orion offers a push-to 6" f/5. It doesn't have motors(which can be a good thing), but it does have a computerised push-to system whereby one simply pushes the telescope whilst noting the object's coordinates displayed on the hand-held controller. It's a go-to of sorts, but without motors... http://www.telescope.com/Telescopes/Dobsonian-Telescopes/IntelliScope-Dobsonians/Orion-StarBlast-6i-IntelliScope-Reflector-Telescope/pc/1/c/12/sc/27/p/102026.uts?refineByCategoryId=27 It's compact, but a bit heavy, for me anyway. It weighs a total of 23.5 lbs(10.7 kg). I'm seeing dark sites not too terribly far from Kolkata... http://static.ibnlive.in.com/pix/slideshow/12-2012/how-indian-cities/india.jpg It is under dark skies that the 6" f/5 would come into its own, and excel.
  4. This kit would be more dependable, durable, versatile and less expensive. The GSO 150mm f/5 Newtonian OTA is superior to Orion's. Also, the mount will accept most any telescope up to 150mm in aperture, including a 60-80mm refractor or spotting scope for daytime use that might be purchased in future... http://www.teleskop-express.de/shop/product_info.php/language/en/info/p26 http://www.teleskop-express.de/shop/product_info.php/info/p8069_TS-Altazimuth-Mount-with-Fine-Adjustment-and-Quick-Release.html http://www.teleskop-express.de/shop/product_info.php/info/p167_TS-1-25--Cheshire-collimat-ng-eyepiece-for-refractors-and-newtonians---metal-tube.html Teleskop Service ships to India, and at very reasonable prices given the distance.
  5. Saswata, Are you planning on purchasing a telescope from the U.S.?
  6. If I'm not mistaken, all fast Newtonians possess a parabolic primary. With Newtonians of longer focal-ratios in the smaller apertures, my understanding has always been that sphericals have been provided instead. A favourable review... http://www.amazon.co.uk/review/R235S5WBP122AW/ref=cm_cr_dp_title?ie=UTF8&ASIN=B000LJSL88&channel=detail-glance&nodeID=560834&store=photo You'll want at least a collimation cap... http://www.firstlightoptics.com/other-collimation-tools/rigel-aline-collimation-cap.html ...if not a Cheshire in addition... http://www.firstlightoptics.com/other-collimation-tools/cheshire-collimating-eyepiece.html
  7. For me, August was delightful due to a drought, albeit with some mosquitoes still. Said conditions drifted into September a bit, but then occasional showers began picking up their pace, although with ample observing nights until recently. Now, here in Novemeber, I've only seen a relatively clear sky for about an hour in the last two weeks. I've always despised rain; the mud and muck in particular.
  8. Hello Saswata, The first and third look to be identical, and both for the same price as well. The second has an alt-azimuth mount, and of a design that I have never seen before. Out of those three, I'd go with the third, the Sky-Watcher, but I have to wonder if Synta manufactured it... I have a 150mm f/5, and it's a great performer... There is one thing however. I don't think you'd be able to use it as a terrestrial/daytime 'scope due to the upside-down image that it would present. Otherwise, if made well, and with a parabolic primary mirror, it would provide very good to excellent views of the night sky. With a SAFE solar filter, it could also be used to observe the sun.
  9. It's nice to see Orion Optics' opticians making Sir Issac proud.
  10. I was carrying this kit around and about the land one night, an Orion "StarBlast 6"... The next day I was miserable, with muscular straining of the abdomen. I recovered after a full day, but no more of that as I then placed the optical tube on a more-manageable, traditional alt-azimuth... I now find that the telescope is even easier to use.
  11. A 12" Newtonian will indeed keep you busy for years to come; decades even. Just be certain to wear an elastic back-brace, from Home Depot or Lowe's, when moving it around and about. Here's an interesting comparison between apertures... http://www.obsessiontelescopes.com/graphics/global/M13_comparison_760px_PNG.png
  12. Thank you, and you're very welcome. I strongly recommend that you do not purchase anything until you have researched further, and to the core. That is most important, whether it takes weeks or months even. Do not be in a hurry, for haste is the enemy in this endeavour. To continue, this is the option for an equatorial to begin imaging, and comes equipped with an autoguider port for guiding during longer camera exposures... http://www.bhphotovideo.com/c/search?N=11124463&InitialSearch=yes&sts=pi The aforementioned CG-4 bundled with the Newtonian is an EQ3-class equatorial, and with a load-rating of approximately 20 lbs. The Exos-2GT is an EQ5-class, and consequently larger and heavier, with a greater load capacity, and necessary to carry not only a telescope but your camera and other accessories without overloading and binding the mount. Therefore a telescope of lighter weight must be stressed. Remember, for instance, if a mount has a 30 lb. load-rating, then your telescope, camera and other accessories necessary for AP must not weigh more than 50-60% of the total load-rating; that is, 18 lbs. Else, the motors will be strained, the mount's gears may bind or strip out, tracking errors would abound, etc. The Exos-2GT is rated for 30 lbs., but for visual use only(18 lbs. max for AP) and is also equipped with go-to technology, for visual use, and also for zeroing in onto objects of interest for the taking of pictures. With the go-to system, one simply enters the desired object to view using the hand controller, and the telescope then slews to its intended target, and hopefully positions the object in the center of the eyepiece when it stops slewing and begins to track. Here's a demonstration of an EQ5-class equatorial with go-to... Now, the telescope itself within the video is a large 8" f/5 Newtonian, and at the mount's extreme limit in handling, for visual use only. For AP, again, the entire load must not exceed a little over half of a mount's load capacity. You may see recommendations for another EQ5-class equatorial, the Celestron Advanced VX, or AVX. It's $220 more than the Bresser Exos-2GT however, and though it comes with an extra feature or two for AP, the AVX's declination axis is known to stick, and due to a simple flat washer used as its bearing. Both axes of the Bresser Exos-2GT utilise ball or roller bearings, for right ascension and declination, and for smoother operation. Astrophotgraphy is quite the other animal in its own right, and when compared to visual observing. Whilst collecting that ancient light from a distant galaxy, a camera must be held in place firmly, and in order to track the galaxy, or any other object, without blurring the resulting image. Also, the mount must track an object steadily and precisely, over a span of several minutes, and also without blurring the final image. Here's an even larger, and more capable EQ6-class equatorial in action, and fully equipped for astrophotgraphy... https://www.youtube.com/watch?v=uJNjvtpjQvk
  13. I have a white-light RG-Film solar filter for my 102mm refractor... I can see the solar disk and sunspots. Others like to see the surface-granulation and flares in addition, and that requires an H-Alpha kit.
  14. Hello, The Vixen A80M 80mm f/11 achromat exhibits minimal CA, but as an achromat it requires a longer focal-length, therefore a longer tube, to keep the CA at a minimum... http://www.vixenoptics.com/Vixen-A80M-Refractor-Telescope-p/2606.htm An 80mm f/16 achromat exhibits virtually no CA, but the tube is considerably longer. At the opposite end, an 80mm f/5 fast-achromat, such as the Orion ST80, exhbits quite a bit of CA when viewing brighter objects. I've no experience in solar-observing with an achromat, however. The Sky-Watcher Pro 80 ED, at f/7.5, would make for a great all-arounder, for both solar system and brighter deep-sky observations with only slight CA evident... http://www.optcorp.com/expired/skywatcher-sizzling-summer-savings/sw-s11100-pro-80-ed-apo-refractor-telescope.html This is an an example of a colour-free apochromat... http://www.optcorp.com/takahashi-fc-76ds-doublet-fluorite-apo-refractor-tfk0761.html White-light solar filters are not heavy at all, especially this RG-Film filter for my 102mm apochromat... http://www.thousandoaksoptical.com/solar.html An H-Alpha system shouldn't weigh much more... http://www.thousandoaksoptical.com/halpha.html Do you have an alt-azimuth or an equatorial mount?
  15. Hello, Deep-sky astrophotography doesn't require a lot of aperture. A fast 80mm ED or apochromatic refractor is an ideal, but that would eat up a good portion of your budget right there. Then there's the equatorial mount, which would be around $600 for the barest minimum for AP. $1000-1500 would get an equatorial recommended for AP, but the mount would be very heavy and cumbersome, yet necessary for serious AP. There is this kit, for visual/observing and a possibility for casual, short-exposure astrophotography... http://www.highpointscientific.com/celestron-omni-xlt-150-telescope-with-dual-axis-motor-drive-31057-md?utm_source=google&utm_medium=cse&utm_term=CEL-31057-MD&gclid=CNLlz9Le68gCFUo6gQodZSQK7Q The included 6" f/5 Newtonian with its 2" focusser is quite popular among amateurs for imaging. It also makes for a great observing telescope, too; and the CG-4 equatorial mount is portable enough, compared to the larger ones. The CG-4 with its motor drives would serve as a primer to get you acquainted with an equatorial and its workings, but it will not serve as a serious, deep-sky imaging platform. With the remainder of the budget you can look into getting a few better-quality eyepieces for observing, and other various and sundry accessories, like a 2x barlow.
  16. I'd get an aluminum adaptor-plate, or make one, then attach it to the SP's mount-plate, then attach the tube rings to the adaptor-plate.
  17. It's definitely a "Bird-Jones", or a "Jones-Bird", reflector, and at f/9. It contains a poor optical lens assembly which barlows the main mirror's inherent, shorter focal-length. Pass that one by. 4.5"(115mm) is a nice portable size. This what a 114mm f/8-f/9 really looks like... http://agenaastro.com/celestron-powerseeker-114eq-telescope-21045.html But I'd go with this instead... http://www.telescope.com/Telescopes/Reflector-Telescopes/Reflector-Telescopes-with-Altazimuth-Mounts/Orion-StarBlast-45-Astro-Reflector-Telescope/pc/1/c/11/sc/342/p/102010.uts
  18. Yes, I recommended an f/5, in light of that very thing. One does get ample contrast for DSOs with a larger secondary; a larger cataract. It just wouldn't be suitable for the fine details on the planets which require telescopes of longer focal-ratios, for both improved contrast and greater magnifications. Then there's that pesky coma which increases the faster the telescope, robbing from an image further. I feel that the atmosphere rules instead. Opinions will differ, to be sure.
  19. Indeed, as much as one may get, but contrast is not as critical for DSOs; aperture is however.
  20. Under dark skies, you can certainly use an f/4 for visual, but perfection in collimating will be more critical for best image, and a coma-corrector preferred. At f/4, it will be decidedly for deep-sky, therefore a contrast-robbing secondary is less of an issue as it would be for the Moon and planets. Going a step slower, with an 8" f/5, would allow for both, deep-sky and the solar system. Said Atlas can easily handle an 8" f/5 for visual, and under dark skies will keep you busy for years... http://www.telescope.com/Telescopes/Reflector-Telescopes/Reflector-Optical-Tube-Assemblies/Orion-203mm-f49-Reflector-Tube-with-Crayford-Style-Focuser/pc/1/c/11/sc/345/p/9788.uts Or... http://www.teleskop-express.de/shop/product_info.php/language/en/info/p49_GSO-200-mm-f-5-Newtonteleskop-Optischer-Tubus---2--Crayford-Okularauszug.html
  21. The Heritage-100P will be great fun, and will show things that relatively few people have ever seen, and for years to come. The included 1.25" eyepieces are larger and much easier to look through than those that came with telescopes when I was young. I started out, at the age of 8 or 9, with a 60mm telescope, and saw Saturn for the first time, and with the yellow eyepiece seen on the right within the following image. Those that come with the 100P will be as those on the left; an extraordinary difference... Telescopes that first appeared on the mass-market back in 1950s and '60s were akin to microscopes, and the eyepieces of that time reflect that; but no more. However there are some who use eyepieces intended for microscopes with their telescopes, and to this day.
  22. Here's M13 when viewing through my 6" f/5 Newtonian(left), and when viewing with my Takahashi FS-102 102mm f/8(right)... The globular cluster appears brighter in the Newtonian, but only slightly. M13 glistened, sparkled even, when I viewed it live through the Takahashi, and when the photograph was taken. But not so when I observed it through the Newtonian; no, not at all. That's one of the advantages of refractors; the best image per inch of aperture, and beyond even in the case of a fine apochromat. At the time I decided upon the Takahashi, there was only one other apochromat that I had considered: the Tele Vue TV102. In the end, the fact that the TV102 exhibited more light-scattering was the deciding factor. What accounts for the FS-102's exceptional control of light-scattering lies within its exquisite calcium-fluorite doublet, not to mention what I describe as its "delicious" multi-coatings... Said control allowed me to split Sirius A and B("The Pup") back in 2003 when the two were practically adjacent to each other. The intense glare from Sirius A could not hide "The Pup" from the Takahashi. Perhaps astoundingly, around the same time, I had read that a 102mm telescope could not split the two.
  23. Hello, I view the act of owning and maintaining a Newtonian telescope as working one's way towards the observing of the heavens. Newtonians require occasional maintenance, in the act of collimation; that is aligning the two mirrors, the primary and secondary, in respect to one another, and to ensure that the telescope provides its very best image. In return one is rewarded with wonderful views, not only within the solar system but also beyond into deep space. If your grandson likes to tinker with things, then a Newtonian would be ideal. The greater the aperture, that is the diameter of the primary mirror, the more that is seen, and what is seen grows brighter and more detailed as the aperture increases. A Newtonian with a primary mirror of 150mm is bright, and will show the young man many objects in space: something new and different one night, or a favourite object revisited on another, and for many years to come. The question is, which 150mm? An f/8, favouring observing within the solar system; or an f/5, which is nicely balanced between observing both: the solar system and deep space? Here is the aforementioned 6" f/8 "Dobsonian"... http://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-150p-dobsonian.html It would be comparable in performance to an unobstructed 120mm f/10 apochromatic refractor. PROS: Simple alt-azimuth motion Collimation less critical, however longer tube makes collimation more difficult Lessened coma More forgiving of eyepiece design and quality Superior lunar and planetary performance CONS: Longer optical tube compared to a 150mm f/5 Newtonian and a 150mm f/10 Schmidt-Cassegrain; less portable Alt-azimuth base of particle-board weighs 10 kg; optical tube weighs 8 kg; entire kit: 18 kg Fixed focusser-position; cannot rotate optical tube for more comfortable eye-placement Narrower field-of-view per eyepiece compared to a 150mm f/5 Mount will not accommodate any other telescopes that may be acquired in future Expensive laser-type collimator may be preferred for longer optical tube The 150mm f/5 with traditional alt-azimuth mount... http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ota.html http://www.rothervalleyoptics.co.uk/skywatcher-az4-1-alt-az-mount-with-aluminium-tripod.html Or, the optical tube bundled with the same mount-head but with heavier steel tripod... http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-az4-mount.html It would be comparable in performance to an unobstructed 120mm f/6 apochromatic refractor. PROS: Wider fields-of-view per given eyepiece Simple alt-azimuth motion OTA with tube rings rotatable for comfortable eye-placement Lighter weight; entire kit weighs less than 11 kg, with aluminum tripod Shorter OTA; portable; travel-friendly More balanced than a 150mm f/8 between solar-system and deep-sky observations; more versatile Ability to mount other telescopes in future; more versatile CONS: More expensive Collimation more critical, however easier with shorter tube and a passive, non-laser collimator Offsetting of secondary mirror recommended Increased coma Barlow is more of a necessity for highest lunar and planetary magnifications possible per a 150mm aperture That said, I get great views, both within the solar system and beyond into deep space, with my 150mm f/5 mounted on a traditional alt-azimuth... M42, the Orion Nebula... M13, the great globular star cluster in the constellation Heracles... M45, the Pleiades, aka "The Seven Sisters"...
  24. MrCat, Any and all eyepieces that you might acquire for your present telescope can be used for telescopes that you may acquire in future. Optically, eyepieces are fully the other half of the telescope. One cannot be used without the other, and are as Punch and Judy; inseparable. Therefore, think nothing of getting one better-quality eyepiece at a time, and so to build a truly fine set; over the weeks, months and years even. Eyepieces are a constant; telescopes less so. This 8mm would be an excellent higher-powered ocular, and with a respectable wide field... http://www.skiesunlimited.co.uk/SLT2/telescope%20eyepieces.html...top, center. The 60° eyepiece is also sold under various house-brands, and praised on both sides of the Atlantic.
  25. The level of said aberration is noticeable within this afocal photograph taken with my Antares 80mm f/6... The camera however, a Canon S110, tends to intesify it, especially the blue. Even less is seen live at the eyepiece. I feel that I received a well-controlled example, per its focal-ratio, but it is nonetheless like playing roulette when considering any fast-achromat manufactured in China, particularly the ever-popular Orion ST80 80mm f/5 sold in the U.S., along with its house-branded siblings sold throughout the world. I almost purchased an Orion ST80 myself, until I discovered and purchased the Antares 805 instead with its superlative 2" GSO rack-and-pinion focusser; and the optical tube of all-metal construction save the focusser knobs and the focusser-drawtube baffles, the latter having been removed upon their discovery and for fear of their cutting into the light-cone. Then there are those who find it bothersome with an 80mm f/11 or a 102mm f/10. It's all a matter of individual preference. I had a Vixen 102mm f/10 for a very short while, then returned it and got a Takahashi 102mm f/8 apochromat instead...
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